Perishable goods are transported on the road in a temperature controlled box that is referred to as a Transport Refrigeration Unit or TRU. TRUs are typically found on semi-trailer tractors and may also be on vans, trucks, railcars and ships. A conventional TRU is powered by an engine that runs on diesel or gasoline fuel to provide the cooling. The engine rotates a shaft that typically powers a compressor that compresses the coolant from a gas to a liquid, and moves the coolant through a condenser and then an evaporator to provide cooling. The engine also powers fans for moving the air in the TRU. Drawbacks to the current configuration are tailpipe emissions, acoustic noise, and many moving parts that cause increased maintenance and downtime. Current state of the art cryogenic TRUs direct inject the coolant into the TRU. This causes oxygen depletion in the TRU and safety concerns. There is a need in the art for a TRU design that overcomes these concerns.